The invention relates to a novel compound that can formed by the chemical or electrochemical oxidation of a B12FxZ12−x2− salt to obtain a compound which can be characterized as:Ma+(B12FxZ12−x−)a wherein a is 1 to 4 and x is at least 3, or at least 5, or at least 8, for the dodecaborate salts; 3≦x≦12; M comprises at least one electrochemically stable cations. Z represents H, Cl, Br, or OR, where R═H, C1-8, preferably C1-3 alkyl or fluoroalkyl. The subscript x can be 4 to 12, 7 to 12 or 7 to 11, and mixtures of salts having x values from 4 to 12, 7 to 12 or 7 to 11. The subscripts “10−x” and “12−x” mean “10 minus x” and “12 minus x” respectively. All other subscripts with the “-” indicate a range, e.g 1-3 means 1 through 3.
The invention also relates compositions comprising the compound and to methods for making and using the compound and compositions.
Divalent salts based on the decaborate and dodecaborate closed cage structure (i.e., B10X102− and B12X122−), are known in the art. The use of these salts has been reported in battery electrolytes, fuel cell electrolytes and other applications. Electrochemical oxidation of B10Cl102−, in acetonitrile gives a purple colored solution, (e.g., as described in Electrochemical Oxidation of Polyhedral Boron Halide Anions, Bowden, J. Electrochem Soc.; Vol 129, No. 6, Page 1249). Chemical oxidation of B10Cl102− with TI(CF3COO)3 in acetonitrile gives a purple product which by UV-vis spectroscopy is identical to the electrochemical oxidation product of B10Cl102−. Chemical oxidation with xenon difluoride was show to form neutral B9Cl9.
Fluorinated B12 derivatives such as B12FxH12−x2− are described in the Cross Reference To Related Patents and Patent Applications above. It was reported (by Ivanov et. al., J. Amer. Chem. Soc., 2003, vol. 125, 4694.) that B12F122− underwent a quasi-reversible oxidation at 4.9 V vs. Li+/0 (ca. 1.9-2.0 V vs. NHE).
There is a need in this art for oxidized radical anion products such as B12FxZ12−x− or B10FxZ10−x−. Such products can impart desirable properties when employed alone or as additives when generated in conventional battery, capacitors or fuel cell electrolytes, or when prepared for use as reagents for carrying out chemical reactions.